No difference in expansion, warpage problems or bolts stretching, so head gaskets not a problem. Good engine in a boat too. Probably not too many around now because irons were only made for 4 years, alloys for 8. If Ford Oz's iron castings in the 70s were all like my 2V clevos, they're likely to be rough as guts. The sand gets rougher as it gets re-used each time. Alloys would have been cast at another plant using different techniques. First ones were made by Honda. They were also designed by them so would have been tweaked in the ports. Sent from my CPH1607 using Tapatalk